Identification of internal boll rot of cotton in Tehran, Golestan and Hormozgan provinces*

Internal boll rot disease is one of the important diseases of cotton. All commercial cotton cultivars, especially the native varietes, are susceptible to the disease. The disease has been reported in pistachio, soybean, and pepper. Changes in the shape and weight of bolls, shedding of buds, flowers and bolls, and the appearance of brown spots on the fibers are symptoms of the disease in cotton. In order to identify the casual agent of the disease, 178 infected boll samples were collected from Tehran, Golestan and Hormozgan provinces, and 17 isolates were obtained from them, and their pathogenicity was evaluated in cotton and bell peppers. Agents were isolated in PDA medium containing yeast extract at a temperature of 30 degrees Celsius. Molecular identification was done by amplification of a part of ribosomal DNA by polymerase chain reaction and ITS1- ITS4 primers. All 17 samples isolated in cotton were pathogenic in Cotton and bell pepper. Two yeast species were identified, Filobasidium magnum was identified for the first time from Tehran province and Meyerozyma guilliermondii is reported for the first time from Iran in the Golestan province .